An internal combustion engine requires heat rejection. Some internal combustion engines are air-cooled while others are liquid-cooled. Internal combustion engines that power automotive vehicles have been liquid-cooled in many cases. Such cooling is accomplished by an engine-driven coolant pump (commonly referred to as a water pump) mounted on the engine block and operated directly by the engine. The pump forces engine coolant through coolant passages in the engine, where the coolant absorbs engine heat, thence through a radiator, where heat is rejected, and finally back to the pump inlet to complete the fluid circuit. A fan that is driven either directly from the engine, or by an electric motor, is used in many cases to draw ambient air across the radiator so that heat is rejected at the radiator by transferring heat from the coolant to the ambient air, thus cooling the engine. A conventional thermostatic valve (commonly, a thermostat) controls the flow of pumped coolant through the radiator in relation to coolant temperature. The thermostat causes restriction of flow through the radiator until the coolant reaches sufficiently hot temperature to cause the thermostat to allow flow through the radiator so that the radiator may effectively limit engine temperature. In this way, the thermostat performs a form of coolant temperature regulation that establishes a desired operating temperature for the engine once the engine has fully warmed up while inherently allowing the coolant to heat more rapidly when the engine is started from a cooler condition.
U.S. Pat. Nos. 3,999,598; 4,475,485; 4,557,223; 4,567,858; 4,691,668; and 4,759,316 show internal combustion engine cooling systems in which heat is rejected by circulating engine coolant through coolant passages of a heat exchanger by using a pump, and in some cases, by also forcing ambient air across the heat exchanger by using an electric motor-driven fan or blower. In some of these patents the heat exchanger is the radiator of an internal combustion engine-powered automotive vehicle. U.S. Pat. Nos. 3,999,598 and 4,475,485 show that the heater core of the heater assembly, which heats the passenger compartment of such a vehicle, is also a heat exchanger through which engine coolant is circulated and across which air is forced by an electric motor-driven blower to deliver heated air to the passenger compartment. U.S. Pat. Nos. 3,999,598; 4,475,485; 4,557,223; and 4,691,668 also show the use of an electric motor to operate the pump that forces engine coolant through the heat exchanger.
The present invention relates to a new and unique total cooling assembly that has important advantages over prior cooling systems, one of the advantages being the facilitation of assembly operations at an automotive vehicle assembly plant.
Briefly, as applied to an engine cooling system, the assembly described herein comprises an assembly composed of several discrete modules: namely, a cooling fan module, an electric coolant pump module, an electronic systems control module, and a heat exchanger module. The cooling fan module is disposed downstream of the heat exchanger module and comprises an electric motor-driven fan for drawing air across the heat exchanger module, so that heat can be continually transferred from the heat exchanger module to the air stream thereby forming the effluent. The electric coolant pump module comprises an electric motor-driven coolant pump for pumping coolant through the engine coolant passages and the total cooling assembly. The electronic systems control module comprises electrical circuitry that receives various inputs and processes those inputs to control the operation of the electric motors of both the coolant pump and the fan. The heat exchanger module comprises a radiator. When the vehicle has an air conditioning system for cooling the passenger compartment, it also comprises an air conditioning condenser in tandem with the radiator; when the vehicle engine is turbo-charged, the heat exchanger module also comprises a charge air cooler. Optionally, an auxiliary cooling fan module may be disposed upstream of the heat exchanger module for creating head pressure across the upstream face of the heat exchanger module.
Another advantage of the invention, as applied to an internal combustion engine, is the elimination of an engine-mounted coolant pump that is driven directly from the engine crankshaft, usually by means of a belt and sheave. This may reduce the volume of the engine's packaging envelope, which may be a significant factor for engine compartment packaging in the design of a new automotive vehicle. The elimination of a belt and sheave reduces the number of engine parts and at the same time eliminates wear problems created by belt side loads on coolant pump shaft bearings. Since an engine-mounted coolant pump that is driven directly by the engine inherently relates the pumped coolant flow rate to engine speed (i.e., engine r.p.m.), such a pump may waste engine power and/or create pump cavitation at times when the coolant flow rate does not have to be as high as the rate to which it is forced by engine r.p.m.
Still another advantage of the invention is the elimination of an engine-driven fan for drawing air across the radiator. This may also reduce the engine's packaging envelope, and eliminate the need for certain engine-mounted parts. Since a fan that is driven directly by the engine draws power from the engine, such a fan may waste engine power at times when ram air flow across the radiator is present.
Further advantages, benefits, features, and utilities of the invention will be disclosed and/or perceived by a reading of the ensuing description and claims, which are accompanied by drawings. The drawings disclose a presently preferred embodiment of the invention according to the best mode contemplated at this time for carrying out the invention.